Wax thread sewing machine



Oct. 29, 1940. o. R. HAAS v WAX THREAD SEWING MACHINE Filed April 24, 1939 1 U gPatented Qct.'29, 1940 v I UNITED, STATES PATENT OFFICE.

om n. Haas, North Beverly, Masa, 'assignor to United Shoe Machinery Corporation, Borough of Fienrlngton, N. 1., a corporation of New ersey Application April 24, 1939, Serial No. 269,566

13 Claims. (01. 112-38) The present invention relates to shoe sewing to which the thread engaging-parts of the mamachines of the waxed thread type, and more chine are heated. A further objectis to propartlcularly to rotary shuttles or loop takers vide an eiiicient sewing machine having a simple for hook needlesewing machines in which the and more economical construction than heretosupply of thread is kept'heated to a temperature fore. I 6 sufficiently high to prevent the wax from con- With these and other objects in view, the gealing before reaching the seam. 1 present invention contemplates the provision of A common problem in all waxed thread sewa wax thread shoe sewins machine a '0- ing machines is in keeping the wax in working tary loop taker formed with the principal thread condition without subjecting it to excessively engaging surfaces of synthetic resin material. 10 high or rapid change in temperature. The waxes While the loop taker, according to the construc-\. employed are generally of low grade, and untion illustrated is provided with a metal beak or less the heat supplied to the thread engaging other reenforcement, in order to furnish greater u parts is carefully regulated to maintain an even streng the Parts are subj 0 unus temperature below a critical point, wax on the strains, such reenforcement is of advantage only thread or accumulations on the parts will bewith the heaviest classes of work, care being come cracked and burned. Asa result, the lutaken to avoid exposure of metal surfaces at bricating and seam sealing qualities of the wax those points where the problem of thread passage g are lost. With improper lubrication of the is acute.

D thread in a hook needle sewing machine the Modern synthetic resins are entirely imper- '0 thread will not pass smoothly'about the thread vious to waxes commonly employed to impregn aging parts, but will become frayed and nate sewing threads and, as a result, there is less i broken. Another cause of damage or broken tendency for the waxes to accumulate on roughthread in a machine of this type is due to obened surfaces of a loop taker.'c0mposed of these I stru tions e nter d by th tm ad in passing materials. Also where the thread is required 9' about the rotary loop taker or shuttle, particuto pass between the loop taker driver and the loop larly of a lockstitch sewing machine wherein a taker, or between the thread 'case and the supply of locking thread is contained within a means for holding the thread case from rotacflse supported by and held from rotation within tion with the loop taker, if synthetic resinma- I 00 the loop taker. In order to permit smooth pasterial is m l ed at one of e c p o sage of loops of needle thread about the'loop oper tin s between h h fi v taker, the surfaces of the loop taker are caregagement' is'made} 'asubstantial reduction in the fully and accurately finished with a high'polish. tendency of the thread to jam results. The re- Roughness or irregularity of any kind on the duction in Jamming may be due eitherto the 8 thread engaging surfaces ofv the loop taker will ability of the resin material to receive a high as result in rapid accumulations of hardened wax polishwith little efiort or from the eflect of its or other materials and thread damage or breaklow heatconducting quality on the wax. Anage. Furthermore, to permit passage of a neeother advantage. of synthetic resin mom of a die loop about a non-rotating thread case held pair of actively cooperating surfaces. is that re- 40 within a loop taker which passes with the thread siliency in the resin causes an absorption 0! ,0 case through the needle loop, there must be a noise and destructive vibration at points where loose engagement between the loop taker and looseness in engagement is necessitated by the its driver, and also between the thread case and passage of thread between said surfaces. the means for holding the thread case from rota- A further feature of the invention relates to 6 tion within the loop taker. 'Insumcient polish? the use in a lockstich shoe sewing machine of a 5 along the cooperating surfaces of these parts cup-shaped loop taker having its circular sidev is particularly destructive to the thread, dueto walls of synthetic resin material arranged to r0- the tendency of the thread to jam at the points taste in a circular heated raceway and to have of contact between the engaging surfaces of the its enclosed locking thread supply heated through 60 parts. v .the resin material of the side walls, thus re-' objects of the present invention are to tardlng the flow of heat transmitted and avoid-' provide a sewing machine of the type indicated ing rapid cooling, cr concentration of heat at in which the difliculties enumerated are to a more exposed points in/the locking thread sup-' ply. This feature vof the invention is embodied in which the locking gs i great extent eliminated and in which there is less A 1 so necessity for accurate control oi. the temperature in a sewing machine supply is further protected. from too rapid cooling or heating by supporting the supply on a bobbin reel also composed of synthetic resin material, and this feature is of advantage either when employed with the loop taker of the type referred to or when employed in a loop taker composed wholly of metal.

These and other features of the invention will be more clearly understood from the following detailed descriptiontaken with'reference to the accompanying drawing.

In the drawing Fig. 1 is a view in front eievation of a portion of a shuttle'for a sewing machine embodying the features of the present invention, parts having been broken away and shown in section; Fig. 2 is a sectional view in side elevation of the parts illustrated in Fig. 1; Fig. 3 is a sectional view of a portion of the shuttle illustrated in Fig. 1 and Fig. 4 is an edgewise view of a metal insert for the shuttle.

The shuttle or loop taker illustrated in the drawing is constructed to operate in a machine similar ,to that disclosed in U. S. Letters Patent to French and Meyer No. 473,870 of April 26, 1892, and cooperates with a curved hook needle II, and other stitch-forming and work feeding devices more fully described in the patent to form a lockstitch seam, a loop of needle thread l2 being indicated in.a position assumed during passage about a supply of locking thread I! contained in a circular thread case It ofusual metal construction, as illustrated in the patent.

The shuttle of the prment invention has a main cup-shaped body It molded from synthetic resin preferably of the phenolic or -urea type base. when molded of these materials, a shuttle results which has sufficiently smooth external surfaces to permit immediate use after the'mold marks and fins have been removed. The nature of the material used is such that even if glassy surfaces are not formed in molding, there is less tendency for wax covered thread to adhere or become frayed by irregularities in the surfacw particularly after said surfaces receive a wax coating from contact with the thread, and those parts of the shuttle engaged by the thread quickly receive a high polish in spite of the war: by mcvementof the thread along them when the shuttle is placed in use. These results are due at least in part to an unusual quality of the resinous material which tends to prevent hardening'orburning of the wax so as to cake and pile up on the thread eng ing surfaces of the resin. Also the advantages in the use of the resinous material may follow from the ability of the material. after long continued use,uto resist grooving by the thread to suohan extent-as occurs. with metal shuttles or loop-takers.

In order to obtain a maximum strength, the illustrated shuttle is suitably reenforced: A reenforcement atthe beak of the shuttle is provided by inserting into the mold in-which the shuttle is formed, a curved steel beak plate member 2| having perforations and dovetailed teeth 2i along one edge to obtain a rlgid'srip in the resin material. The tip of the metal member has the same shape as the beak of the shuttle'in the patent, but below the tip the member is're-' duced in width so as to be covered by wedge- -shaped.portions 22 of the resin shuttle body,

. which portions assist in the needle loops in their passage about the shuttle. The inserted member also is formed-with an outer rib 28 merging with the outer circumferential line of the shuttle to provide a wearing surface en'- gaged by a raceway 2| on the machine frame in which the shuttle is rotatably supported. The

shuttle body is further reenforced by strips of canvas 26 or other material having fibres running lengthwise about the circular side walls of the cup-shaped body and also from the circular I side walls into an end wall of the cup formed by the body.

when the needle I0 withdraws from the work with a loop of needle thread in the machine of the patent, it is transferred from the hook of the needle to the shuttle, sliding over the beak and into the throat of the shuttle, as indicated in Fig. 1. In entering the throat of the shuttle, the thread passes between cooperating surfaces on the shuttle, and on the lowermost' arm of .a shuttle driver 28 similar to that disclosed in the patented machine. The driver 28 is secured to a shaft Ill mounted in bearings in the machine frame and arranged to rotate first in a counter-clockwise direction to cause the needle loop l2 to be .carried about the shuttle! and thread case, and then in a clockwise direction to return the shuttle to its original position. To rotate the driver 28 in this manner, the rearward end of the shaft has secured to it a bevel gear 22 meshing with a toothed segment 34 at the end for passage of the needle loop 12. Before the shuttle reaches the end of its counter-clockwise rotation, the needle loop has passed between the lowermost arm of the driver a and is moving along the surface of the-shuttle towards the uppermost arm of the driver, To provide a space for the thread between the uppermost arm and the shuttle body, the shuttle continues to rotate after the driver 22 reaches the end of its counterclockwise rotation either, through its own momentum or due to the tension on the needle loop l2 until the space between the lowermost arm of the driver 28 and the shuttle body is closed, and the surface engaged by the uppermost arm of the driver moves away from said arm. As a result of the relative movement between the driver and the shuttle, a continuous series of impacts is produced with the cooperating surfaces of the shuttle and, when the machine is operated at high speeds. the shuttle may vibrate at high periodicity at the end of each rotation even while the needle thread is passing between the arms of the driver and the cooperating surfaces of the shuttle 'body.,-thus-causing the needle thread to be pinched and retarded in itsmovement along the surfaces of the shuttle body. Also the wax becomes hardened and burned causing the parts to stick together, further retarding the movements of the thread. With the use of synthetic resin in the present machine, the impacts between the c operating surfaces of the driver and shuttle are substantially reduced with a resulting reduction in noise and vibration. The tendency of thepartsto adhere fromhardenedwaxso as to retard the movement of th'e'thread riaily lessened.

A similar thread retarding action in the machiucofthepatent'occursastheneedleloopis is also mate-" thread sewing machine formed withthread enbeing drawn from the shuttle between the thread case and a retainer arm 40 pivoted at 42 to the frame or the machine, the thread case being formed with a projecting nose 44, the sides of which are engaged loosely by surfaces on the retaining arm. The space between the retainer and thread case may become choked with hardened wax. To facilitate'movement of the needle loop, and to reduce the effects of vibration of the nose of the thread case between the cooperating surfaces on the retainer arm 40 in the present machine, a slotted block 46 of a resin material similar to that which forms the shuttle body is secured to a recess in the arm ill, the sides oithe slot in the block surrounding the nose it.

As in'the machine of the patent, the raceway 25 for the shuttle has mounted within it a heating element II to conduct heat to the raceway and through the circular walls of. the cup-shaped shuttle body into the locking thread supply within the thread case. The temperature of the parts thus heated is usually controlled by a valve or an electrical rheostat which is adjusted according to the operators judgment. Where the machine is not used continuously, the heater may be left on or turned oil and on a number of times become cracked and hardened and a,more even distribution of the heat in the thread supply is effected.

To further retard the flow of heat towards and from the thread supply, and to provide an eflective construction which may be manufactured more economically than heretofore, the, supply in the thread case of the machine illustrated is contained on a bobbin reel Ill composed in its entirety of molded synthetic resin. Thus, with the circular walls of the shuttle body acting to retard the flow of heat to the thread case, the supply on the reel is eil'ectivelyF guarded against the eflects of sudden heating or cooling by the central tubular sleeve and side flange portions of the reel 80.

The nature and scope of the present invention having been indicated, and a specific embodiment having been described, what is claimed is:

l. A rotary loop taker for use in combination with the stitch-forming devices 'of a waxed gaging surfaces of synthetic resin material.-

2. A rotary loop taker for use in combination with the stitch iorming devices of a -waxed thread shoe sewing machine formed with thread engaging surfaces of waxed synthetic resin material and a pointed metal beak.

3. A rotary loop taker for use in combination with the stitch-forming devices of a waxed thread shoe sewing machine formed with thread engaging surfaces of synthetic resin material and a.

pointed metal beak' embedded within the'material of the loop taker and arranged with wedge portions of resin material at either side, the

surfaces of which wedge portions act to spread 22: needle loop during passage about the loop 5. A waxed thread lockstitch shoe sewing machine having, in combination, stitch-forming devicesincluding a locking thread supply case, means for supporting the thread case and for carrying loops of needle thread about the thread case comprising a needle thread loop taker, formed with thread engaging surfaces of waxed synthetic resin material, and a metallic driver between which and the loop taker the needle loops pass arranged to contact the'loop taker along certain of said surfaces with a loose engagement to provide spaces through which the needle loop passes as it is carried about the thread case.

6. A waxed thread lockstitch shoe sewing machine having, in combination. stitch-forming devices including a locking thread supply case, means for supporting the thread case and for carrying loops of needle thread about the thread case comprising a needle thread loop taker, and retaining means between which and the thread case the needle loops pass provided with thread case engaging surfaces of waxed synthetic resin material to hold the thread case from rotation with the loop taker.

7. A waxed thread lockstitch sewing machine having, in combination, stitch forming devices including a rotary loop taker, a locking thread supply casesupported by the loop taker and ar-' ranged with a projecting member to be held from rotation as the loop taker-rotates; and a thread case retainer comprising an arm movable towards and from the thread case and a slotted block'of synthetic resin material carried by the arm to surround the projecting member of the thread case.

8. A waxed thread lockstitch shoe sewing machine having, in combination, stitch-forming devices including a locking thread supply case, means for supporting the thread case and for carrying loops of needle thread about the thread case comprising a needle thread loop taker of synthetic resin material and a heated raceway in which the loop taker is supported, arranged '-to transmit heat through resin walls of the l0.-A waxed thread lockstitch shoe sewing machine having, in combination, stitch-formin devices including a locking thread supply case, and

' means for supporting the thread case and for carrying loops of needle thread about the thread case comprising a cup-shaped needle thread loop wall of the cup.

11. A waxed thread iockstitch shoe sewing machine having; in combination, stitch-forming devices including a locking thread supply case, means for supporting the thread case and for carrying loops of needle thread about the thread case comprising a needle thread loop taker, formed of synthetic resinmaterial, a raceway in which the loop taker is supported for rotary movement, and a metallic insert embedded in the material of the loop taker forming swearing surface engaged by the raceway.

12. A waxed thread lockstitch shoe ma chine having. in combination, stitch-forming devices including a locking thread supply case, means for supporting the thread case and for carrying loops of needle thread about the thread case comprising a needle thread ioop'taker ibrmed or rynthetiereain materiaharaoewayin which the loop taker is supported for rotary movement, and a metallic loop beak plate embedded within the material'ot the loop meansiormpportingthethreadcaseandtor carryingloopdotneedlethreadaboutthethread case comprising a needle thread loop takeriormedwithcircularsidewallsoisyhtheticresinmateriahaheatedracewayinwhichtheloop -taker is supported arranged to transmit heat throughthecircmarresinwallsoithelooptaker to the locking thread supply within the thread case, and athread'supply reel within thethread case having side flanges otunthetic resin matel-n1 A antennas. 

